Uv curable catalyst compositions

ABSTRACT

UV curable compositions and methods for depositing one or more metal or metal alloy films on substrates are disclosed. The UV curable compositions contain a catalyst, one or more carrier particles, one or more UV curing agents, and one or more water-soluble or water-dispersible organic compounds. Metal or metal alloys may be deposited on the substrates by electroless or electrolytic deposition.

BACKGROUND OF THE INVENTION

The present invention is directed to UV curable catalyst compositionsand methods of depositing an ultra-thin metal or metal alloy layer on asubstrate. More specifically, the present invention is directed to UVcurable catalyst compositions and methods of depositing an ultra-thinmetal or metal alloy layer on a substrate where the UV curable catalysthas high surface area particles.

Many industries where workers desire to coat or form one or more metalor metal alloy layers on substrates employ catalysts. Such catalysts areemployed in electroless deposition of metal or metal alloys. Electrolessdeposition or plating is based on the presence of a chemical reducingagent being added to the deposition bath. Such chemicals supplyelectrons to substrate metals, which transmit the electrons to thepositively charged metal ions in the bath reducing these ions to metalin the same manner in which electric current reduces metal ions tometals in electrolytic or electrodeposition baths.

Electroless plating produces several desirable results. Workers oftenhave difficulty in depositing metal layers of uniform thickness onsubstrates with crevices or holes using electrolytic methods of plating.This attribute is important in many industries such as in theelectronics industry, in which printed circuit or printed wiring boardsdemand uniform metal deposits plated into high aspect-ratiothrough-holes. Other properties and applications of electroless platingare deposits which may be produced directly upon nonconductors, depositsin which are often less porous than electrolytic plating, and alsodeposits which often have unconventional chemical, mechanical ormagnetic properties (such as higher hardness and wear resistance).

Another attribute of electroless plating is that the process isauto-catalytic and deposition occurs on a catalytic surface.Accordingly, a catalyst is required. Catalysts employed in electrolessmetal deposition vary widely in composition depending on the metal ormetal alloy to be deposited as well as the use of the article made. Inaddition to the manufacture of printed wiring boards, electrolessplating using catalysts are employed in the manufacture of variousdecorative articles, and in numerous other electronic applications suchas in the formation of electromagnetic interference (EMI) and radiofrequency interference (RFI) shielding.

EMI radiation is created by operation of many diverse forms ofelectronic equipment ranging from microwave equipment to home computers.The radiation occurs because electronic devices emit “noise” in afrequency range of 60 Hz to more than 1000 MHz, and is picked up byother devices or by conduction through power lines that act as antennas.EMI radiation may interfere with other devices and has been known tocause such diverse problems as interference with police mobile radios,communication systems, scientific test equipment and cardiac pacemakers.

One approach to limiting electromagnetic containment is the use of anEMI shield to contain the radiation. Containment requires specialshielding materials, components, and structures, which prevent generatedenergy from escaping and acting as a source of disturbance.

Effectiveness of electromagnetic containment is determined by the degreeto which the field strength is attenuated as a result of reflection orabsorption by the shielding material. Shielding efficiency is calculatedas a logarithmic function of the ratio of unshielded EMI transmission toshielded EMI transmission and is expressed in decibels (db). Because ofits logarithmic nature, an increase of 30 db in shielding efficiency fora given wavelength or frequency of electromagnetic radiation representsa 1000% increase in the shielding efficiency of a coating. A coatingwith a shielding efficiency of 30 db, for example, eliminates 99.9% ofthe total EMI radiation. A 60 db coating eliminates 99.9999% of thetotal EMI radiation.

A number of different shielding methods have been used commercially. Onemethod involves applying a metallic coating over a plastic housing forelectronic devices. Such methods include galvanic deposition, spraycoating such as by arc-spraying or spraying the metal on as a paint,cathode sputtering, chemical metallizing and vacuum metallizing. Metalcoatings have included copper, silver, chromium, nickel, gold and zinc.Such methods have suffered from a number of deficiencies such as macroor microscopic cracking, peeling of coatings, limited shieldingeffectiveness, oxidation of metals in the coatings, distortion ofthermoplastic substrates, and expensive application equipment.

A more suitable method of forming an EMI shield has been by electrolessdeposition of a metal on the non-conductive housing materials.Electroless deposition of non-conductors such as plastics involvedimmersing a part in a series of aqueous baths, which both prepare thesurface of the part for deposition and permit metallization. Followingconventional pretreatment steps, the part is then immersed into acatalyst containing noble metals, such as a colloidal tin/palladiumcatalyst, to render non-conductive surfaces catalytic to deposition ofthe desired plating metal. Following catalysis, the part is thenimmersed into an electroless plating bath containing dissolved metalswhich, in contact with the plating catalyst, results in deposition of acoating of the metal onto the catalyzed surface.

While the foregoing electroless catalyst and method was superior to manyof the earlier methods employed to address the problem of EMI shielding,the electroless coating process was not selective. The entire part wasimmersed into the colloidal catalyst solution followed by immersing thepart into a metal plating solution. The result was that metal was platedover the exterior as well as the interior surface of the non-conductorpart. Where aesthetics are important in the marketing of electroniccomponents, an exterior metal coated housing for the electroniccomponent is undesirable. Typically, the industry paints the housing.This is a time consuming and wasteful step, especially where housingsare most often molded in a desired color.

U.S. Pat. No. 5,989,787 discloses an alkaline, hydrophilic activatingcatalytic solution for selectively electroless plating of metals on anon-conductive substrate. The solution is composed of a mixture ofcopper lactate or zinc lactate, a palladium salt, such as palladiumchloride, and an alkaline medium. The electroless plating methodincludes the steps of applying the hydrophilic activating catalyticsolution on a substrate to form a photosensitive film on the substrate,and selectively exposing the photosensitive film to UV (ultra-violet)radiation or scanned by laser rays to deposit palladium catalyst on thesubstrate, developing away any un-exposed photosensitive film, andelectroless plating the substrate using the palladium catalyst as anactivating catalyst.

When the photosensitive film is exposed to UV radiation or scanned bylaser rays, copper ions or zinc ions from the copper or zinc lactate areactivated to interact with palladium ions. The palladium ions are thenreduced to metallic palladium thereby depositing catalytic palladium onthe substrate. The patent states that the formation of palladium lactateis important in the performance of this invention because palladiumlactate is soluble in the alkaline environment. As stated in the patentthe highly soluble palladium lactate permits a distinct contrast betweenthe radiation exposed area and non-exposed area with a short timeexposure to the radiation. Further, because the lactate is not likely tobe subjected to hydrolytic decomposition, the un-exposed photosensitivefilm may be removed with water or water-based liquids without formingunnecessary compounds. One disadvantage of the composition and methoddisclosed in the '787 patent is the use of only palladium salts for thecatalyst. Such salts are typically more expensive than other catalyticsalts. Further any undeveloped palladium lactate is lost during therinse steps resulting in the lose of costly palladium metal.

Another disadvantage of the composition and method of the '787 patent isthat it does not disclose methods of adhering palladium to thesubstrate. Accordingly, in order to prepare the substrate for receivingthe palladium, classic chromic etch methods would be used. Such chromicetch methods are undesirable because they are hazardous to workers, andany waste generated in their use is environmentally unfriendly.

Accordingly, there is still a need for an improved composition andmethod of forming a metal layer on a non-conductive substrate.

SUMMARY OF THE INVENTION

Compositions of the invention include a catalyst, one or more carriershaving an average particle size of from 5 nm to 900 nm, one or more UVcuring agents, and one or more water-soluble or water-dispersibleorganic compounds. The compositions do not employ organic solvents asthe water-soluble or water-dispersible organic compounds providesufficient means of adhesion for the compositions to a non-conductivesubstrate. Accordingly, roughening a non-conductive surface with asolvent swell is avoided when using the compositions, thus eliminatingmany potentially hazardous compounds from the compositions. Thenano-sized carrier particles, on which the catalysts are coated,increase the effective area of the catalysts, thus permitting acontinuous catalytic layer to be placed on a substrate. The catalyticlayer permits electroless metals to nucleate and grow through thecatalytic layer to the substrate permitting the substrate to come intoelectrical contact with deposited metal. Further, the compositions areUV curable enabling rapid throughput and, with the use of a suitabledeveloper, the creation of discrete patterns and clearly demarcatedmetallized areas. Such imaging of the catalytic layer can be used tocreate, for example, waveguides, antenna for electronic devices and toenable the creation of tracks for electronic circuitry.

Another embodiment is directed to a method of depositing a metal ormetal alloy on a substrate that includes applying a UV curable catalyticcomposition to the substrate, the catalytic composition includes acatalyst, one or more carriers having an average particle size of from 5nm to 900 nm, one or more UV curable agents, and one or morewater-soluble or water-dispersible organic compounds; and depositing ametal or metal alloy on the substrate with the catalytic composition.

An additional embodiment is directed to an article made with the UVcurable compositions comprising a substrate having one or more metal ormetal alloy layers and a resistance of 50 mΩ/cm² or less. Articles madewith the compositions and methods may be employed in numerous electronicdevices, for example, such as in printed circuit or wiring boardsincluding embedded passives such as resistors and capacitors, for EMIshielding, RFI shielding, optoelectronic devices, for polymer or ceramicfibers for ESD clothing, and decorative features on various articles.The compositions and methods may be employed in any industry where metaldeposition is employed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a SEM at 2000× of copper selectively deposited with a UV curedcatalyst on an FR4 substrate.

FIG. 2 is another SEM at 2000× of copper selectively deposited with a UVcured catalyst on an FR4 substrate.

FIG. 3 is a SEM at 2000× of a plurality copper bars selectivelydeposited with a UV cured catalyst on an FR4 substrate.

DETAILED DESCRIPTION OF THE INVENTION

As used throughout the specification, the following abbreviations havethe following meaning, unless the context clearly indicates otherwise: °C.=degrees Centigrade; gm=gram; mg=milligram; L=liter; mL=milliliter;A=amperes; m=meters; dm=decimeter; mm=millimeters; μm=micron=micrometer;cm=centimeter; nm=nanometers; mΩ=milliohms; cps=centipoise;kV=kilovolts; SEM=scanning electron micrograph; terms “plating” and“depositing” are used interchangeably throughout the specification;terms “printed wiring board” and “printed circuit board” are usedinterchangeably throughout the specification; “film” and “layer” areused interchangeably throughout the specification; “water-soluble”within the scope of the present invention means that a compound orpolymer swells or dissolves in water at normal temperatures (from above0° C. to 100° C. at 1 atmosphere pressure); “water-dispersible” withinthe scope of the present invention means that a compound or polymerforms an emulsion, micro-emulsion or suspension in water at normaltemperatures. All numerical ranges are inclusive and combinable in anyorder, except where it is logical that such numerical ranges areconstrained to add up to 100%.

Compositions include catalysts in the form of hydrous oxides orhydroxides of catalytic metals dispersed in an aqueous diluent with oneor more inert carrier or filler particles, one or more UV (ultra-violet)curing agents, and one or more water-soluble or water-dispersibleorganic compounds. Inert carrier or filler particles are not believed toparticipate in the catalytic reactions during metal or metal alloydeposition. The compositions form aqueous slurries.

Hydrous oxides or hydroxides of catalytic metals may be formed by anysuitable method known in the art. For example, metal hydrous oxides maybe formed by preparing an aqueous solution of a salt of a desired metalwith agitation, pH adjustment and heat as needed to obtain dissolutionof the metal salt. Thereafter a hydrolysis and nucleation reaction ispermitted or caused to take place at a controlled rate within thesolution. The reaction takes place until a hydrous oxide is formed insitu. The hydrolysis reaction is permitted to continue until thesolubility limit of the solution is exceeded to form a separatedispersed phase. Such methods are well known by those of skill in theart.

Any suitable metal, which forms a hydrous oxide or hydroxide and hascatalytic properties, may be employed to practice the present invention.Examples of suitable metals include silver, gold, platinum, palladium,indium, rubidium, ruthenium, rhodium, osmium, and iridium. Examples ofother catalytic metals include copper, cobalt, nickel, and iron (in theferric oxidation state). Typical catalytic metals include silver, gold,and platinum. More typically, silver, and gold are the choice of noblemetals, and most typically, silver is the choice for the catalyticmetal. The foregoing list of metals is not exhaustive and any metal thatforms a hydrous oxide or hydroxide and has catalytic properties withrespect to the metal or metal alloy to be deposited may be employed topractice the present invention.

Choosing a metal catalyst depends on the metal or metal alloy to bedeposited on a substrate. In electroless deposition of a metal or metalalloy, the oxidation/reduction potential of the catalytic metal is moreelectropositive (‘noble’) than that of the metal or metal alloy to bedeposited. For example, the following metals are reported to becatalytic to the deposition of copper, copper alloy, nickel, nickelalloy, and cobalt: silver, tellurium, platinum, thallium, vanadium,gold, germanium, selenium, iron, and palladium, with gold, platinum andsilver typically employed. More typically silver and gold are employedto deposit copper or an alloy of copper. Most typically silver isemployed to deposit copper or a copper alloy.

The catalyst in the form of a metal hydrous oxide or metal hydroxide ismixed with one or more inert carriers to form an aqueous slurry. Inertcarriers employed may be any suitable water-insoluble compound having anaverage particle diameter such as from 5 nm to 900 nm, or such as from20 nm to 600 nm, or such as from 50 nm to 500 nm. While not being boundby theory, the catalytic metals as their hydrous oxides or hydroxidesare adsorbed onto the inert carrier particles, thus increasing theeffective catalytic area of the catalysts, which allows the metalcatalysts to come into more intimate contact with a plating bath thanwith carrier particles of greater average sizes. This intimate contactis believed to enable formation of ultra-thin catalytic films. Suchcatalytic films, when dry, range in thickness of from 10 nm to 10microns or such as from 50 nm to 10 microns. Metal ions depositing asmetal are believed to nucleate through the catalytic composition to forman electrical contact with the substrate, and form a continuous metal ormetal alloy film over the substrate. Such nucleation is of value in manyapplications such as, for example, when constructing electrical tracesin a printed wiring board, solder-pads for chip-capacitors, capacitors,or electrical components in general where electrical contact is desired.

Suitable carriers include, but are not limited to, variouswater-insoluble salts and minerals or mixtures thereof. Examples of suchsuitable inert carriers include, but are not limited to, compounds ofmulti-valent cation and anion pairs, metal oxides, silicates, silica ormixtures thereof. The inert carriers are included in slurries of thepresent invention in amounts such as from 30 times the weight ofcatalytic metal in the hydrous oxide or hydroxide compound and greater,or such as from 55 to 330 times the weight of the catalytic metal in thehydrous oxide or hydroxide compound, or such as from 60 to 300 times theweight of the catalytic metal. Surface areas of ultra-fine inert carrierparticles may range from 0.5 m²/gm to 3000 m²/gm or such as from 50m²/gm to 2000 m²/gm, or such as from 100 m²/gm to 1000 m²/gm or such asfrom 200 m²/gm to 800 m²/gm.

Examples of suitable compounds of multi-valent cation and anion pairsinclude, but are not limited to, water-insoluble salts of barium,calcium, magnesium, and manganese such as barium sulfate, calciumhydroxide, magnesium hydroxide, manganese hydroxide, or mixturesthereof. Barium salts and calcium salts are more typically employed suchas barium sulfate or calcium hydroxide or mixtures thereof. Barium saltssuch as barium sulfate are most typically employed.

Examples of suitable metal oxides include, but are not limited to, ironoxide, aluminum oxide, titanium dioxide, calcium carbonate, zinc oxide,magnesium oxide cesium oxide, chromium oxide, hafnium oxide, zirconiumoxide, or mixtures thereof. Aluminum oxide, calcium carbonate, zincoxide, or mixtures thereof are more typically employed. Aluminum oxide,calcium carbonate or mixtures thereof are the most typically employedoxides.

Examples of suitable silicates include, but are not limited to,gemstones (except diamond), beryl, asbestos, clays, feldspar, mica,talc, zeolites, both natural and synthetic zeolites, or mixturesthereof. Examples of natural zeolites include analcite, chabazite,heulandite, natrolite, stilbite and thomosonite. Zeolites, clays, micasor mixtures thereof are more typically employed silicates.

Any suitable water-soluble or water-dispersible organic compound may beemployed in the slurries of the present invention. The organic compoundsare believed to perform as binders for the catalysts and carrierparticles. While not being bound by theory, the organic compounds arebelieved to bind to the substrates by hydrogen bonding, ionic bonding,covalent bonding, van der Waals forces or combinations thereof. Othertypes of chemical bonds and electrostatic forces may be involved. Thebonding ability of the organic compounds with the substrate eliminatesthe need for a solvent to swell or roughen a substrate surface.Accordingly, many undesirable solvents that are toxic to workers and ahazard to the environment are excluded from the compositions of thepresent invention.

Examples of suitable water-soluble or water-dispersible organiccompounds include, but are not limited to, polyurethanes and epoxides ormixtures thereof. Other suitable water-soluble or water-dispersibleorganic compounds include, but are not limited to, polymers such asacrylic homopolymers or copolymers, lactic acid homopolymers orcopolymers, polyamides, polyesters, alkyd resins, ethylene copolymerswith acrylates or vinyl acetate, chlorinated or unchlorinatedhomopolymers or copolymers of vinyl chloride, vinyl acetate or vinylproprionate, cyclisized or chlorinated rubber, nitrocellulose, ethyl orethylhydroxy cellulose, coumarine-indene resins, terpene resins,polyvinyl acetal resins, cellulose esters such as celluloseacetobutyrate and cellulose acetoproprionate, shellac, polyalkylglycols, starch, carbohydrates and other natural resins singularlyor in combination. Additionally, fine-sized ion exchange materials maybe used as dispersants. For example, suitable ion exchange resinsinclude those with olefinic, styrenic, acrylic and vinyl backbones,which contain quaternary amine groups, amino-acetic, carboxylic andsulfonic functionality. Such organic compounds compose from 5 wt. % to60 wt. % or such as from 10 wt. % to 45 wt. % or such as from 20 wt. %to 35 wt. % of the catalytic composition.

Examples of suitable polyurethanes include, but are not limited to,aqueous based, polyurethane compositions. Such compositions may be ionicaqueous dispersions of polyurethane containing ionic or hydrophilicfunctional groups as well as hydrophobic polyolefin segments in thebackbone. The dispersions may be cationic or anionic. Such aqueousdispersions are known in the art and are commercially available and maybe made by various methods disclosed in the literature.

An example of one method of preparing aqueous based,polyurethane-polyolefin dispersions includes renderingisocyanate-terminated polyurethane prepolymers water-dispersible byincluding in the prepolymer chain an effective amount ofwater-dispersing pendent carboxylic or cationic salt groups orcombinations thereof. Typically, pendent carboxylic or cationic groupscompose from 0.5 wt. % to 10 wt. % of the prepolymer. Methods of formingsuch prepolymers are well known to those of skill in the art. Examplesof preparing such prepolymers and aqueous based, polyurethane-polyolefindispersions are disclosed in U.S. Pat. No. 4,644,030. Alternatively, theprepolymer may be devoid of carboxylic or cationic salt groups in whichcase the prepolymer is dispersed in water with the aid of a dispersingagent, such as one or more non-ionic surfactant.

Isocyanate-terminated polyurethane prepolymers may be prepared by anysuitable method known in the art. Many methods are disclosed in theliterature. An example of a method of preparing an isocyanate-terminatedpolyurethane prepolymer involves reacting organic material containing anaverage of at least 2 active hydrogen atoms per molecule, such as a diolor a polyester polyol, with a stoichiometric excess of an organicdiisocyanate. Many such organic diisocyanates suitable for makingisocyanate-terminated polyurethane prepolymers are well known in the artand many are commercially available. The organic material may contain atleast one unreactive pendent carboxylic group in salt form orneutralized with a suitable basic material to salt form during or afterprepolymer formation. An example of such carboxylic-containing reactantis an alpha, alpha dimethylol (C₂ to C₁₀) alkanoic acid, such as2,2-dimethylol propionic acid.

In addition to polyester polyols, other polyols or mixtures thereof maybe employed and include, but are not limited to, poly-caprolactone,polycarbonate, polybutadiene resins (hydroxyl terminated homopolymers ofbutadiene), polyethers based on ethylene oxide, propylene oxide andtetrahydrofuran, or mixtures thereof.

Examples of suitable polyisocyanates include, but are not limited to,methylene bis isocyanato-cyclohexane, ethylene diisocyanate, propylenediisocyanate, butylene-1,3-diisocyanate, 1,6-hexamethylene diisocyanate,2,2,4-trimethyl-hexamethylene diisocyanate,2,4-dimethyl-6-ethyloctamethylene diisocyanate, cyclohexylenediisocyanate, cyclopentylene diisocyanate,1,4-diisocyanatomethyl-cyclohexane, 1,3-diisocyanatoethyl-cyclohexane,toluylene diisocyanate,3,3,5-trimethyl-1-isocyanato-5-isocyantomethyl-cyclohexane,2-butene-1,4-diisocyanate, isophorone diisocyanate, 1,6-hexamethylenediisocyanate biuret, 1,6-hexamethylene diisocyanate trimer, isophoronediisocyanate trimer, bis phenol A dimethacrylate capped with2-hydroxyethylmethacrylate capped with 1,6-hexamethylene diisocyanatetrimer, or mixtures thereof.

Many of the foregoing diisocyanates may be purchased from Lyondell(located in Houston, Tex.) or Bayer (located in Pittsburgh, Pa.).Additional examples of commercially available polyisocyanates includeMONDUR CB (adduct of 3 moles toluene diisocyanate with 1 moletrimethylol propane, Mobay Chem.), DESMODUR-N (trifunctional biuret of1,6-hexane diisocyanate, Mobay Chem.), ISONATE 143 L (polymericdiisocyanate bis phenyl isocyanate, Upjohn).

Optionally, a suitable proportion of the organic activehydrogen-containing reactant material or the organic isocyanate reactantmaterial contains at least one ethylenically unsaturated group, suchproportion is sufficient to include from 0.5 wt. % to 60 wt. % or moreunits derived from such unsaturated group-containing reactants in theurethane polymer. Such groups provide cross-linking capability whensubjected to subsequent in situ vinyl addition polymerization conditionsfor polymerizing liquid inert monomer material in the polyurethanedispersion. The organic reactant material for this purpose may beprovided with these unsaturated groups in any suitable form or linkages,e.g. ether, ester, or carbon-to-carbon linkages. Examples of such activehydrogen-containing materials include, but are not limited to, glycerolmono allyl ether, glycerol methacrylate, N,N-dimethylol-1 butene,hydroxy terminated poly(butadiene), hydroxethylacrylate,hydroxypropylacrylate, or mixtures thereof. Examples of suchisocyanate-containing reactants include, but are not limited to,2-methyl-5-vinylbenzene-1,4-diisocyanate and1-(α-isocyanato-α-methyl)ethyl-3 (α-methyl)ethenyl benzene (m-TMI, Amer.Cyanamid). Ethylenic unsaturation may appear in pendent groups along thepolyurethane chain, in terminal groups, or internally as links in thechain or any combination thereof.

The synthesis of isocyanate-terminated polyurethane prepolymer may becarried out in the presence of inert liquid polymerizable ethylenicallyunsaturated monomer material. Such monomer materials are well known inthe art, yielding polyolefins (including substituted polyolefins) or“vinyl addition polymers”, i.e. by the addition polymerization of one ora mixture of monomers containing one or more internal terminalpolymerizable ethylenically unsaturated groups. This type ofpolymerization is known as suspension polymerization and is carried outin the presence free radical vinyl polymerization catalysts or redoxsystems where the monomers add to each other at ethylenic double bondsto produce polymer chains composed predominantly of carbon atoms.

Monomer materials typically are liquid under the prepolymer-formingreaction conditions. The monomer materials function as the solvent,diluent or carrier medium. Optionally, organic solvents may be added tothe reaction medium. Examples of suitable monomers include, but are notlimited to, polymerizable ethylenically unsaturated hydrocarbons,carboxylic acids, esters and ethers, such as free acids and esters ofacrylic and methacrylic acid, esters and ethers of vinyl alcohol, andstyrene. Illustrative examples include butadiene, isoprene, styrene andsubstituted styrenes, the free acids and lower alky (C₁ to C₆) esters ofacrylic, methacrylic acid and maleic acid, vinyl acetate, butyrate,acrylate and methacrylate, hexanediol, diacrylate, vinyl methyl, propyland butyl ethers, divinyl ether, divinyl sulfide, trimethylol propanetriacrylate, 2-butane-1,4-diol diacrylate, or mixtures thereof.

The foregoing illustrative examples of suitable monomeric materialinclude both mono- and poly-ethylenically unsaturated materials, thelatter providing cross-linking capability under vinyl additionpolymerization conditions. Polyunsaturated materials, include, but arenot limited to, di-ethylenically unsaturated materials and when employedmay be mixed in minor amounts with mono-ethylenically unsaturatedmaterials, i.e. in amounts ranging from 1 to less than 50 wt. % of thepolymerizable ethylenically unsaturated monomers. The monomer materialmay be composed of one or a mixture of such mono-ethylenicallyunsaturated material.

In addition to the inclusion in the prepolymer chain of pendent anioniccarboxylic salt groups, a desired water-dispersibility may alternativelybe provided by the inclusion in the chain of an equivalent proportion,i.e. an effective amount, of pendent water-dispersing cationic saltgroups. Such cationic salt groups include, but are not limited to,quaternary ammonium groups, insertable, for example, by employing asuitable proportion of an active hydrogen-containing organic reactantcontaining a tertiary amine or alkyl halide group and subsequentlyquaternizing these groups by reaction with, respectively, an alkylhalide or a tertiary amine. Organic or inorganic acid salts of tertiaryamine groups in the prepolymer also are effective water-dispersingcationic salt groups.

The prepolymer may undergo conventional chain extension followed byvinyl addition polymerization with polymerizable ethylenicallyunsaturated monomer material to polymerize the monomer material in situ.Such methods are well known in the art. An example of suitable chainextenders is polyamines such as aliphatic polyamine, which are reactivewith isocyanate groups. Completion of polymerization is indicated by aconstant solids content ranging from 20 wt % to 60 wt %. The aqueousdispersions have a pH of from 7 to 9.5 when anionic and from 2 to 10when cationic. Viscosities range from 25 to 200 cps at from 18° C. to25° C.

Examples of suitable water-dispersible or water-soluble epoxy resinsinclude, but are not limited to, epoxy resins produced from variousphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol AD,hydroquinone, resorcin, methyl resorcin, bisphenol, tetramethylbiphenol, dihydroxynaphthalene, tetrabromobisphenol A, dihydroxydiphenylether, dihydroxydibenzophenone, dihydroxydiphenyl sulfone phenol novolakresin, cresol novolak resin, bisphenol A novolak resin,dicyclopentadiene phenol resin, terpene phenol resin, phenol aralkylresin, naphthol novolak resin or brominated phenol novolak resin, orvarious phenol-type compounds such as polyhydric phenol resins obtainedby condensation reactions of various phenols and various aldehydes, suchas hydroxybenzaldehyde, crotonaldehyde or glyoxal, and epihalohydrin.Also, for example, epoxy resins produced from various amine compoundssuch as diaminodiphenyl methane, aminophenol or xylene diamine, andepihalohydrin. Epoxy resins produced from various carboxylic acids alsomay be employed such as methylhexahydroxyphthalic acid or dimmer acid,and epihalohydrin. Mixtures of the various epoxy resins may be employed.Many of the foregoing epoxy resins are commercially obtainable or may beprepared by methods disclosed in the literature.

Typically, epoxy resins derived from bisphenol A, bisphenol S, bisphenolF or novolak resins, or epoxy resins obtained by reaction of bisphenol Aand epihalohydrin, or mixtures thereof are employed. More typically,epoxy resins derived from bisphenol A, novolak resins or epoxy resinsobtained by reaction of bisphenol A and epihalohydrin are employed, ormixtures thereof. Most typically, epoxy resins derived from bisphenol Aare used.

Any suitable compound which cures the compositions upon exposure to UVradiation may be used. Examples of such compounds include onium saltsand compounds which generate a free-radical upon exposure to UVradiation. UV curing agents may be used in amounts of 0.1 wt % to 15 wt% of the composition, or such as from 1 wt % to 10 wt %, or such as from3 wt % to 7 wt %.

Suitable onium salts include, but are not limited to, onium salts inwhich the onium cation is iodonium or sulfonium such as onium salts ofarylsulfonyloxybenzenesulfonate anions, phosphonium, oxysulfoxonium,oxysulfonium, sulfoxonium, ammonium, diazonium, selenonium, arsonium,and N-substituted N-heterocyclic onium in which N is substituted with asubstituted or unsubstituted saturated or unsaturated alkyl or arylgroup.

The anion of the onium salts may be, for example, chloride, or anon-nucleophilic anion such as tetrafluoroborate, hexafluorophosphate,hexafluoroarsenate, hexafluoroantimonate, triflate,tetrakis-(pentafluorophosphate) borate, pentafluoroethyl sulfonate,p-methyl-benzyl sulfonate, ethylsulfonate, trifluoromethyl acetate andpentafluoroethyl acetate.

Examples of typical onium salts include, for example, diphenyl iodoniumchloride, diphenyliodonium hexafluorophosphate, diphenyl iodoniumhexafluoroantimonate, 4,4′-dicumyliodonium chloride, dicumyliodoniumhexafluorophosphate, N-methoxy-a-picolinium-p-toluene sulfonate,4-methoxybenzene-diazonium tetrafluoroborate,4,4′-bis-dodecylphenyliodonium-hexafluoro phosphate,2-cyanoethyl-triphenylphosphonium chloride,bis-[4-diphenylsulfonionphenyl]sulfide-bis-hexafluoro phosphate,bis-4-dodecylphenyliodonium hexafluoroantimonate and triphenylsulfoniumhexafluoroantimonate.

Photoinitiator chemicals include, but are not limited to, n-phenylglycine, aromatic ketones (benzophenone,N,N′-tetramethyl-4,4′-diaminobenzophenone [Michler's ketone],N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzophenone,3,3′-dimethyl-4-methoxybenzophenone,p,p′-bis(dimethylamino)benzophenone,p,p′-bis(diethylamino)-benzophenone, anthraquinone,2-ethylanthraquinone, naphthaquinone, phenanthraquinone, benzoins(benzoin, benzoinmethylether, benzoinethylether, benzoinisopropylether,benzoin-n-butylether, benzoin-phenylether, and methylbenzoin,ethybenzoin), benzyl derivatives (dibenzyl, benzyldiphenyldisulfide, andbenzyldimethylketal (SIC)), acridine derivatives (9-phenylacridine,1,7-bis(9-acridinyl)heptane), thioxanthones (2-chlorothioxanthone,2-methylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone,and 2-isopropylthioxanthone), acetophenones (1,1-dichloroacetophenone,p-t-butyldichloroacetophenone, 2,2-diethoxyacetophenone,2,2-dimethoxy-2-phenylacetophenone, and2,2-dichloro-4-phenoxyacetophenone).

Optionally, surfactants may be added to the catalytic compositions ofthe present invention provided that they do not interfere with thecatalysis of metal deposition. Suitable surfactants include cationic,anionic, amphoteric, non-ionic or mixtures thereof. Surfactants areincluded in conventional amounts. Examples of suitable non-ionicsurfactants are ethylene oxide/propylene oxide copolymers sold by BASFunder the Pluronic® and Tetronic® tradenames.

Optionally, coalescing agents may be added to the catalyticcompositions. Any suitable coalescing agent may be added to thecatalytic compositions. Examples of suitable coalescing agents include,but are not limited to, glycols and glycol ethers or mixtures thereof.Coalescing agents are employed in conventional amounts.

Optionally, additional adhesion promoting organic compounds may beincluded in the catalyst compositions of the present invention. Examplesof such adhesion promoting compositions include, but are not limited to,triazines, phenols, aldehydes, acrylic esters, imidazoles, acrylamide,benzotriazole, malonates, acetoacetates, chlorinated polyolefins,urethanes such as Eastman Chemical AP 440-1, epoxybutene, glycidylmethacrylate, alkoxysilane compounds such asβ-(3,4-epoxycyclohexyl)ethyltriethoxysilane,bis(trimethoxysilylpropyl)amine, γ-aminopropyltrimethoxy silane andaminoalkyl siloxanes.

Components of the UV curable catalytic compositions of the presentinvention may be mixed together by any suitable means known in the art.One method is to utilize high-shear dispersion to coat the ultra-fineinert filler with a catalyst and then to add resin to the filler underlow-shear agitation. Suitable shear rates are well within the ability ofa person of skill in the art and minor experimentation may be performedto determine optimum shear rates for a given composition. Mixing may becarried out at temperatures of, for example, such as from 15° C. to 35°C., more typically from 18° C. to 25° C. The mixture of componentsresults in an aqueous slurry, which may be applied to a substrate by anysuitable means known in the art. For example, the slurry may be appliedby immersing a substrate into the slurry or the slurry may be sprayedonto the substrate using a suitable spray apparatus such as an air gun.Brushing and screening are other examples of methods of applying thecatalytic compositions. Optionally, a mask or a tool having a desiredpattern may be applied to the substrate prior to applying the catalyticcomposition such that the catalytic composition is selectively depositedon the substrate, thus a metal or metal alloy film may be selectivelydeposited on the substrate during the plating process.

Alternatively, the entire substrate may be coated with the catalyst anddried on the substrate. A mask or photo-tool with a desired pattern maythen be applied to the dried catalyst. The coated substrate with thephoto-tool is then exposed to UV radiation to cure the exposed portionsof the catalyst. The photo-tool is then removed and a suitable developeris applied to the substrate to remove the un-exposed portions of thecatalyst. Any suitable developer may be used. Examples of suchdevelopers include water, aqueous based liquids such as aqueous bases,and mono-alcohols such as methyl, ethyl, propyl, isopropyl, polyols andmixtures thereof. Other suitable developers include N-methylpyrrolidone, butyl methacrylate, and mixtures thereof.

A wet film of from 0.5 to 30 microns is formed on a substrate surface,or such as from 1 to 20 microns or such as from 5 to 15 microns. The wetfilm is then allowed to dry. Drying may be performed by any suitablemethod. An example is to let the film air-dry. Air-drying may take from20 minutes to 2 hours, more typically from 60 minutes to 90 minutes.However, drying time may be shorter or longer depending on the ambientconditions of the drying room. Dry film weight may range from 0.5 gm/m²to 10 gm/m² or such as from 1 gm/m² to 5 gm/m².

Catalyst compositions of the present invention may be applied to anysuitable substrate. Examples of such substrates include, but are notlimited to, nonconductors such as plastics, which may be thermoplasticor thermosetting resins. Exemplary thermoplastic resins include, but arenot limited to, general-purpose plastics such as PE (polyethylene), PVC(polyvinyl chloride), PS (polystyrene), PP (polypropylene), ABS(acrylonitrile-butadiene-styrene), AS (acrylonitrile-styrene), PMMA(polymethyl methacrylate), PVA (polyvinyl acetate), PVDC (polyvinylidenechloride), PPO (polyphenylene oxide), and PET (polyethyleneterephthalate); general-purpose engineering plastics such as PA(polyamide), POM (polyacetal), PC (polycarbonate); PPE (modifiedpolyphenylene ether), PBT (polybutylene terephthalate), GE-PET (glassfiber reinforced polyethylene terephthalate) and UHPE(ultrahigh-molecular weight polyethylene); and super-engineeringplastics such as PSF (polysulfone), PES (polyethersulfone), PPS(polyphenylene sulfide), PAR (polyarylate), PAI (polyamideimide), PEEK(polyetheretherketone), PI (polyimide) and fluorocarbon resins.Exemplary thermosetting resins include, but are not limited to, phenolicresins, urea resins, melamine resins, alkyd resins, unsaturatedpolyesters, epoxy resins, diallyl phthalate polymers, polyurethanes andsilicone resins.

Other materials that may be employed as substrates in practicing thepresent invention include, but are not limited to, rubbers, ceramics ingeneral including ceramic fibers, silicates, glass includingnon-silicate glass and glass fibers, wood, fiber-reinforced plastics,textiles, and paper.

After the catalytic composition (also known in the art as a primer) hasdried on the substrate, the dried primer is cured using any suitable UVcuring procedure and source of UV radiation. Optionally, the driedprimer and the substrate may be baked at temperatures of 30° C. to 100°C., or such as from 40° C. to 80° C. Baking may range from 5 minutes to60 minutes, or such as from 10 minutes to 30 minutes. Many suchprocedures are known in the art. One method is to expose the substratewith the dried primer to UV rays from an excimer-lamp at wavelengths offrom 170 nm to 400 nm, or such as from 200 nm to 375 nm. UV curing maybe performed at any suitable temperature. For example UV curing may beperformed at temperatures of from 18° C. to 40° C. or such as from 20°C. to 30° C. The time period for UV curing may range from 2 seconds to60 seconds, or such as from 15 seconds to 30 seconds.

After curing, a metal or metal alloy may be deposited on the catalystcomposition by any suitable method known in the art. If the catalystcomposition was applied to the substrate using a patterned tool or mask,the metal or metal alloy is selectively deposited. Typically, metals aredeposited on the primed substrate by electroless metal deposition. Asubstrate with a cured primer is sprayed with an electroless bath or isimmersed in the bath for a sufficient amount of time to deposit acontinuous metal or metal alloy film on the substrate. Such proceduresare well known in the metal plating industry.

Any metal that may be deposited by electroless deposition may beemployed to practice the present invention. Examples of suitable metalsthat may be electrolessly deposited using the catalyst compositionsinclude, but are not, limited to copper, nickel, cobalt, chromium, iron,tin, lead, aluminum, magnesium, chromium, vanadium, zinc, and theiralloys. Examples of alloys that may be employed to practice the presentinvention include, but are not limited to, copper/nickel, copper/silver,copper/tin, copper/bismuth, tin/silver, tin/lead, nickel/vanadium,nickel/boron, nickel/phosphorous, cobalt/phosphorous, andnickel/cobalt/phosphorous. Other metals that may be deposited using thecatalyst compositions include, but are not limited to, gold, silver,platinum, palladium, indium, rhodium, ruthenium, iridium, osmium, andtheir alloys. Typically, copper, nickel, cobalt, lead, gold, silver,platinum, palladium and their alloys are deposited using the catalystcompositions, more typically copper, nickel, gold, platinum, palladiumand their alloys. Most typically copper and copper alloys are depositedusing the catalyst compositions.

Electroless plating baths for depositing a metal or metal alloy on asubstrate are well known in the art and vary in composition. As anexample electroless metal plating baths may contain one or morediluent-soluble metal salts as a source of the metal or metal alloy tobe deposited, complexing agents, chelating agents, reducing agents,stabilizers, and brighteners. Other components may be included in suchelectroless baths as are well known to those of skill in the art.

Continuous metal or metal alloy films deposited using the catalyticcompositions may vary in thickness such as from 10 nm to 10 microns orsuch as from 0.1 microns to 5 microns, or such as from 0.5 microns to 2microns.

Surface resistance of the metal or metal alloy films may vary. Suchsurface resistance may be from 50 mΩ/m² or less, or such as from 0.05mΩ/m² to 30 mΩ/m², or such as from 1 mΩ/m² to 15 mΩ/m².

Surface hardness of the metal or metal alloy film may vary. Typicallysurface hardness, as measured by ASTM D3363, ranges from 6B to 6H, withhigher hardness's (3H or higher) more typical in order to protect theintegrity of metal or metal alloy layers during post-plating assemblywhere damage to the continuity of the layers may occur. Such hardness isdesirable as for EMI shielding where holes or cracks in the metal maycompromise the shielding performance of the metal layer. The ASTM D3363procedure is well known in the art and hardness is tested with pencilshaving varying graphite hardness.

Articles made with the catalyst compositions and methods may be employedin numerous electronic devices, for example, such as in printed circuitor wiring boards including embedded passives such as resistors andcapacitors, for EMI shielding, RFI shielding, optoelectronic devices,for polymer or ceramic fibers for ESD clothing, and decorative featureson various articles.

Optionally, metal and metal alloy films deposited by catalysts andmethods disclosed herein may be further metallized with one or moreadditional metal or metal alloy layers. Such additional metal layers ormetal alloy layers may range in thickness from 0.5 microns and higher,or such as from 10 microns to 20 microns. Such additional metal or metalalloy layers may be deposited by electroless metal deposition or byelectrolytic deposition. Electroless metal deposition also includesimmersion metallization methods. Such additional metallization methodsare well known in the art.

Electroless metals that may be deposited include, but are not limitedto, copper, nickel, cobalt, chromium, magnesium, aluminum, bismuth,lead, vanadium, iron, tin and their alloys. Other metals include, butare not limited to, gold, silver, palladium, platinum, rhodium,ruthenium, osmium, iridium, and their alloys. Examples of suitablemetals that may be plated by immersion processes include, but are notlimited to, gold and silver.

The following examples are included for illustration of some embodimentsof the invention. They are not intended to limit the scope of theinvention.

EXAMPLE 1 A UV Catalytic Primer of Hydrous Oxide of Silver

A stock solution of hydrated silver hydroxide is prepared by mixing 50gm of silver nitrate (AgNO₃) with 10 gm of sodium hydroxide (NaOH) atroom temperature (18° C. to 20° C.), which forms a brown precipitate ofhydrated silver oxide. The precipitate is allowed to settle and then iswashed with a sufficient amount of deionized water to bring the pH to 9.

0.1 gm of the hydrated silver oxide is then added to an aqueouscomposition containing 2.5 gm of barium sulfate (BaSO₄) having anaverage particle size of 300 nm, 0.25 gm of iron oxide (Fe₂O₃) having anaverage particle size of 550 nm and 8.75 gm of water. The solids aredispersed in the water under high-shear agitation using a stirringapparatus. 1.2 gm of an aqueous emulsion of Bisphenol-A epoxy resin withan average molecular weight of 1300 equivalent weights is then added andmixed under low-shear using a stirring apparatus until a uniform slurrywas formed.

A suspension of 0.3 gm of oxysulfonium containing onium salt UV curingagent, 0.1 gm of propylene glycol methyl ether and 1 gm of water aremixed with the slurry containing the hydrous silver oxide until all ofthe components formed a uniform slurry. The ratio of inert filler tometal catalyst was 30 to 1.

EXAMPLE 2 A UV Catalytic Primer of Hydrous Oxide of Silver

0.045 gm of the stock hydrated silver oxide from Example 1 is added toan aqueous composition containing 2.5 gm of barium sulfate (BaSO₄)having an average particle size of 300 nm, 0.15 gm of iron oxide (Fe₂O₃)having an average particle size of 550 nm, 0.5 gm di(ethyleneglycol)butyl ether, 1 gm of diphenyl iodonium chloride, and 9 gm ofwater. The solids are dispersed in the water using high-shear agitation.0.8 gm of an aqueous-dispersed polyurethane resin containing hydrophobicsegments in its backbone and 0.01 gm of an alkoxysilane cross-linker areadded to the slurry using low-shear agitation. The ratio of inert fillerto metal catalyst is 65 to 1.

EXAMPLE 3 A UV Catalytic Primer of Hydrous Oxide of Silver

0.045 gm of the stock hydrated silver oxide from Example 1 is added toan aqueous composition containing 3.6 gm of barium sulfate (BaSO₄)having an average particle size of 300 nm, 0.25 gm of iron oxide (Fe₂O₃)having an average particle size of 550 nm, 0.5 gm di(ethyleneglycol)butyl ether, 0.5 gm of diphenyl iodonium hexafluorophosphate, and6 gm of water. The solids are dispersed in the water using high-shearagitation. 0.8 gm of an aqueous-dispersed polyurethane resin containinghydrophobic segments in its backbone is added to the slurry usinglow-shear agitation. The ratio of inert filler to metal catalyst is 94to 1.

EXAMPLE 4 A UV Catalytic Primer of Hydrous Oxide of Silver

0.043 gm of the stock hydrated silver oxide from Example 1 is added toan aqueous composition containing 4.5 gm of iron oxide (Fe₂O₃) having anaverage particle size of 550 nm, 0.5 gm di(ethylene glycol)butyl ether,0.5 gm of n-phenyl glycine, and 6 gm of water. The solids are dispersedin the water using high-shear agitation. 0.8 gm of an aqueous-dispersedpolyurethane resin containing hydrophobic segments in its backbone and0.01 gm of an alkoxysilane cross-linker is added to the slurry usinglow-shear agitation. The ratio of inert filler to metal catalyst is 114to 1.

EXAMPLE 5 Copper Film Surface Resistivity

Hydrous silver oxide is prepared by combining 50 gm of silver nitrate inone liter of water and then mixing with a sufficient amount of sodiumhydroxide to bring the pH of the mixture to 9 to form a brownprecipitate of hydrous silver oxide.

The hydrous silver oxide is filtered and then washed with deionizedwater. 0.045 gm of this hydrous silver oxide are then added to anaqueous composition containing 2.5 gm of barium sulfate (BaSO₄) havingan average particle size of 300 nm, 0.15 gm of iron oxide (Fe₂O₃) havingan average particle size of 550 nm, 0.5 gm di(ethylene glycol)butylether, 0.5 gm of triphenyl sulfonium hexafluoroantimonate and 9 gm ofwater. The solids are dispersed in the water using high-shear agitation.0.8 gm of an aqueous-dispersed polyurethane resin containing hydrophobicsegments in its backbone are then added using low-shear agitation.

Six ABS coupons are coated with the hydrous silver oxide catalyst usingan air gun to deposit the catalyst on the ABS to form dry catalyticlayers of 1 gm/m², 2 g/m², 3 g/m², 5 g/m², 6 g/m² and 8 g/m². Curing isdone using an excimer YAG (365 nm) laser. Each coupon is then platedwith 1.5 microns thick copper film using Coppermerse® 80 copperelectroless plating bath (obtainable from Rohm and Haas ElectronicMaterials LLC, Marlborough, Mass.). Plating is done at 40° C. for 40minutes to form a 1.5 microns thick film on each coupon.

A second set of six ABS coupons are coated with the hydrous silver oxidecatalyst using an air gun to deposit the catalyst on the ABS to form drycatalytic layers of 1 gm/m², 2 gm/m², 3 gm/m², 4 gm/m², 6 gm/m² and 8gm/m². Curing is done with an excimer YAG (365nm) laser. Each coupon isthen plated with a copper film of 1.5 microns using Coppermerse® 80electroless-copper plating bath. Plating is done for 40 minutes at 38°C.

Surface resistivity of the copper films is measured for each of thetwelve coupons using a Versatronic R-100 resistance meter with a4-electrode probe system. An average surface resistivity of 4 mΩ/cm² isexpected for the copper films.

EXAMPLE 6 Catalyst of Hydrous Oxide of Palladium

A 1% wt. solution of palladium chloride is dissolved in 100 mL of water.The mixture is stirred until the palladium chloride is dissolved. Asufficient amount of sodium hydroxide is added to the solution toprovide a pH of 3 to form a brown hydrous oxide dispersion. Thedispersion is filtered and washed with deionized water.

0.1 gm of the hydrous oxide of palladium is mixed with 8 gm of bariumsulfate having an average particle diameter of 500 nm, 1 gm2-cyanoethyl-triphenyl phosphonium chloride, and 2 gm of a cationicdispersion of a polyurethane containing hydrophobic segments in itsbackbone using a sonic mixer. A sufficient amount of water is added tothe dispersion to bring the volume to 500 mL. The dispersion is mixed toform a slurry. The primer is applied to an ABS polymer substrate, whichis to be plated with a metal from an electroless metal bath. Aphoto-tool is applied to the coated ABS substrate. The primer is curedusing an excimer lamp (172 nm). The unexposed portion of the primer isdeveloped with ethyl alcohol. Copper is then electrolessly plated on thecoated substrate using a conventional method and bath. The metal platingon the completed article may function as an EMI or RFI shield.

EXAMPLE 7 Catalyst of Hydrous Oxide of Platinum

A 1% wt. solution of platinous dichloride is formed by dissolving thesalt in 100 mL of dilute hydrochloric acid at 80° C. After cooling toroom temperature, the pH of the solution is raised to 3 with sodiumhydroxide to form a precipitate of hydrous oxide of platinum. Theprecipitate is filtered and washed with deionized water.

0.1 gm of the precipitate is then mixed with 5 gm of iron oxide with anaverage particle size of 50 nm, 5 gm of barium sulfate with an averageparticle size of 120 nm, 0.1 gm of benzophenone and 3 gm of an anionicdispersion of a polyurethane containing hydrophobic polyolefin segmentsin its backbone. The composition is mixed using a high shear mixingapparatus to form a slurry.

The catalyst primer is applied to a silicate substrate, which is to beplated with a metal from an electroless metal bath. A photo-tool isapplied to the primer coated silicate substrate, and then is exposed toUV radiation using an excimer lamp (300 nm). The unexposed portions ofthe primer are developed with isopropyl alcohol. The silicate iselectrolessly plated with copper. The metal film may function as an EMIor RFI shield.

EXAMPLE 8 Catalyst of Hydrous Oxide of Copper

A 1% wt. solution of cupric chloride is formed by dissolving the cupricchloride in 100 mL of water. The solution is then heated to 70° C. andadjusted with sodium hydroxide to a pH of 6. A precipitate of hydrousoxide of copper is formed.

0.2 gm of the hydrous oxide of copper is mixed with 15 gm of analciteparticles having an average size of 400 nm along with 2 gm of abisphenol S-type epoxy resin, 0.1 gm of 2-chlorothioxanthone, and asufficient amount of water to provide 1 liter. Mixing is done with ahigh shear stirring apparatus.

The slurry is applied as a catalyst primer to a polystyrene substrate. Aphoto-tool is applied to the coated polystyrene and then exposed to UVradiation at 275 nm using an excimer lamp. The unexposed primer isdeveloped away with isopropyl alcohol. The polystyrene is then platedwith copper. The metal films may function as EMI or RFI shields forvarious electronic articles.

EXAMPLE 9 Catalyst of a Hydrous Oxide of Gold

A 1% wt. solution of auric chloride is dissolved in 100 mL of water. ThepH of the solution is raised over a period of 2 days to 5 with asufficient amount of sodium hydroxide. During raising of the pH thesolution is continuously stirred and heated to 40° C. to form a brownhydrous oxide of gold precipitate. The precipitate is filtered andwashed.

0.3 gm of the precipitate are mixed with 15 gm of silicate particleshaving an average diameter of 100 nm, 5 gm of barium sulfate particleshaving an average size of 10 nm, and 3 gm of a bisphenol F-type epoxyresin, 1 gm of diphenyl iodonium chloride and enough water to bring thevolume to one liter. Mixing is down with a high shear stirringapparatus.

The catalyst primer applied to an ABS substrate, is cured using anexcimer lamp (275 nm) then plated with gold using an electroless metalplating bath. The metal film may function as an EMI or RFI shield in anelectronic article.

EXAMPLE 10 UV Curable Catalyst of Hydrous Oxide of Silver

A stock solution of hydrated silver hydroxide was prepared by mixing 50gm of silver nitrate (AgNO₃) with 10 gm of sodium hydroxide at 20° C.,which formed a brown precipitate of hydrated silver oxide. Theprecipitate was allowed to settle and was then washed with a sufficientamount of deionized water to bring the pH to 9.

1 gm of hydrated silver oxide was then added to an aqueous compositioncontaining 27 gm of barium sulfate (BaSO₄) with an average particle sizeof 300 nm and 1.5 gm of CG250 iodonium salt (obtainable from CibaGeigy). The solids were dispersed in water under high-shear agitationusing a stirring apparatus. 8.5 gm of bisphenol-A epoxy resin with anaverage molecular weight of 715 equivalent weights and 18 gm of butylcarbitol acetate (coalescing agent) was then added and mixed underlow-shear using a stirring apparatus until a uniform slurry was formed.

The slurry was applied to an FR4/glass-epoxy substrate, allowed to airdry for 30 minutes and then baked at 65° C. for 30 minutes. A photomaskhaving three different patterns was applied to the coated FR4 substrateand exposed to UV radiation at 325 nm for 1 minute. Isopropyl alcoholwas then applied as a developer to remove the unexposed portion of thecoating from the substrate.

The substrate was then placed into a commercial electroless copperplating system (Coppermerse® 80 from Rohm and Haas Electronic Materials,LLC). The electroless plating was done at 43° C. for 45 minutes todeposit 1.5 microns thick copper layers. The substrate was then removedfrom the plating system, rinsed with deionized water and dried at 20° C.

FIGS. 1, 2 and 3 show the copper deposited on the FR4 substrate in theshape of a star, arrow and a series of copper bars, respectively. Theedges formed by copper deposits were smooth and discrete. The surfaceresistance for the copper coatings were less than 10 mΩ/cm².

An adhesion test was conducted according to ASTM 3359 in which a 2mm-spaced cross-hatch pattern was scribed onto the copper patterns andPermacel® tape was adhered over the scribe marks and then pulled off tosee if any of the scribed-coating de-adheres. No de-adhesion wasobserved.

1-7. (canceled)
 8. A method comprising: a) applying a catalyticcomposition to a substrate, the catalytic composition comprises acatalyst, one or more carriers having average particle sizes of from 5nm to 900 nm, one or more UV curing agents, and one or morewater-soluble or water-dispersible organic compounds; and b) curing thecatalytic compositions; and c) depositing a metal or metal alloy on thesubstrate with the catalytic composition.
 9. The method of claim 8,wherein the UV curing agents comprise onium salts, free-radicalgenerators, or mixtures thereof.
 10. An article comprising a substrateand a metal or metal alloy nucleating with the substrate made accordingto the method of claim 8.